1. Field of the Invention
This invention relates to a photothermographic silver halide material and process for producing in such a material improved post-processing image stability by means of a 6-substituted-2,4-bis(trichloromethyl)-s-triazine stabilizer precursor.
2. Description of the State of the Art
Photothermographic silver halide materials for producing an image by thermal processing are known. Such photothermograpic materials can include a photolytically active stabilizer precursor, such as described in U.S. Pat. No. 3,874,946.
A stabilizer or stabilizer precursor is necessary in a photothermographic material because such a material is designed to eliminate a fixing step that normally would remove undeveloped silver. Such a photothermographic material is described in, for example, Research Disclosure June 1978, Item No. 17029. The stabilizer precursor is a means to provide post-processing stabilization to enable room-light handling capability following thermal processing. Stabilizer precursors for this purpose in photothermographic silver halide materials are, for instace, 2-tribromomethylsulfonylbenzothiazole and 2,4-bis(tribromomethyl)6-methyltriazine described in U.S. Pat. No. 3,874,946. These photolytically active stabilizer precursors, however, adversely affect photographic speed and storage stability prior to thermal processing.
Other known stabilizer precursors exhibit one or more of the following disadvantages:
reduced stability of the photothermographic material prior to thermal processing of the photothermographic material, PA0 reduced photographic speed, PA0 insufficient stabilization either to thermal instability of the photolytic stabilizer precursor at processing temperature, or to PA0 insufficient light absorption above about 300 nanometers. PA0 (a) photographic silver halide, PA0 (b) an image forming combination comprising PA0 (a) 2-bromo-2-arylsulfonylacetamides, such as 2-bromo-2-p-tolylsulfonylacetamide, PA0 (b) 2(tribromomethyl sulfonyl) benzthiazone and PA0 (c) 6 substituted-2,4-bis(tribromomethyl)-s-triazines, such as 6-methyl or 6-phenyl-2,4-bis(tribromomethyl)-s-triazine. PA0 (I) a hydrophilic photosensitive silver halide emulsion with PA0 (II) an organic solvent mixture comprising PA0 (III) comprising